Hume's experimental psychology and the idea of erroneous preferences

Hume's Treatise of Human Nature is not only a canonical text of philosophy, but also a pioneering work of psychology, anticipating many findings of modern behavioural economics. According to Hume's theory of mind, the concept of rationality does not apply to choices or moral judgements. But in his theory of justice, Hume explains preference reversals between smaller-sooner and larger-later options in terms of farsighted ‘true’ preferences and psychologically-induced errors of short-sightedness. Anticipating a common idea in behavioural welfare economics, he proposes a role for government in helping individuals to overcome self-control problems in acting justly. I examine Hume's position and assess its coherence. I conclude that Hume's theory of mind is consistent and psychologically well-grounded, but does not support the concepts of true preference and error that appear in his theory of justice. However, the fundamental logic of that theory does not depend on assumptions about self-control problems.